GB2118523A

GB2118523A - Inflatable gripper

Info

Publication number: GB2118523A
Application number: GB08308624A
Authority: GB
Inventors: Kurt Kriechbaum; Rainer Studtmann; Johann Walk; Fritz Haller
Original assignee: Schubert und Salzer Maschinenfabrik AG
Current assignee: Rieter Ingolstadt Spinnereimaschinenbau AG
Priority date: 1982-04-16
Filing date: 1983-03-29
Publication date: 1983-11-02
Also published as: FR2525244A1; CH659493A5; IN157025B; DE3214128A1; US4472934A; GB8308624D0; GB2118523B; FR2525244B1; DE3214128C2; BR8301858A; IT8320497A0; IT1163245B

Description

(112)UK Patent Application (i.,GB (11) 2 118 523 A (21) Application No

8308624 (22) Date of filing 29 Mar 1983 (30) Priority data (31) 3214128 (32) 16 Apr 1982 (33) Fed Rep of Germany (DE) (43) Application published 2 Nov 1983 (51) INT CL3 B66C 1146 (52) Domestic classification BSH KA U1S 1671 1381-1 (56) Documents cited GB 1491456 GB 1197223 GB 1116500 GB 1040513 GB 1001327 GB 0862069 (58) Field of search B8H (71) Applicants Schubert and Saizer Maschinenfabrik AG, (FIR Germany), Fried rich-Eb ery-Strasse 84, 8070, Ingoistadt Fed Rep of Germany (72) Inventors Kurt Kriechbaum Rainer Studtrnann Johann Walk Fritz Hailer (74) Agent andlor Address for Service Marks and Clerk, 57-60 Lincoln's Inn Fields, London WC2A 31-S (54) Inflatable gripper (57) An inflatable gripping device for bobbin changing on spinning or twisting machines has a resiliently deformable sleeve (3) inserted in a housing (2), the housing and the sleeve both being bell-shaped. The sleeve (3) engages over the edge (20) of the housing (2) and is pressed against the edge (20) in an airtight mianner by a screw collar ring (4). The sleeve is inflated by compressed air entering the housing and is shaped to provide cylindrical and conical parts which respectively contact the bobbin tube (5) and the end winding layers of yarn.

PATENTS ACT 1977 SPECIFICATION NO 2118523A

The following corrections were allowed under Section 117 on 12 January 1984:

Front page, Heading (7 1) Applicants below (FR Germany), for FriedrichEbery-Strasse read Friedrieli-Ebert-Strasse THE PATENT OFFICE 16 February 1984 C CV. & Bas 25560113 G) m 1 SPECIFICATION

Pneumatic gripping device The invention relates to a pneumatic gripping device for bobbin changing devices on spinning or twisting machines, having a gripping device housing and a resiliently deformable sleeve which is arranged in the gripping device housing and may be pressed against the external periphery of a bobbin 75 tube by means of compressed air.

A pneumatic gripping device with a resiliently deformable sleeve, which is pressed against the external periphery of a bobbin tube by the supply of compressed air into the gripping device is known (DE-PS 1,180,285). This gripping device for draw-off apparatus on continuously operating bobbin chang ing devices for spinning machines has a gripper head which is connected to a compressed air source by means of a flexible tubing and is mounted so as to be freely movable in its mounting in order to equalize oscillations in movement. A tube is secured to the lower part of the gripper head and is used to accommodate an annular sleeve which has a U-shaped cross-section and is made of rubber.

Compressed air may be led into or let out of the annular sleeve through a longitudinal bore in the gripper head, the outer and inner edges of the annular sleeve being pressed in an airtight manner against the gripper head. When compressed air is led in the inner part of the annular sleeve is pressed against the free end of the bobbin tube, which end projects out over the tube winding, so that the bobbin tube is secured in the gripper opening of the gripping device and the bobbin may be removed by lifting the gripping device from the spindle. When the gripping device releases the bobbin a push rod, which projects into the gripper opening and is required for the centering of the gripper head in its mounting, acts as an ejector.

The disadvantage in the case of the known gripping device is the complicated manufacture and the relative movement of the annular sleeve with respect to the wall of the tube surrounding it which occurs during the supply of compressed air into the 110 gripping device. Owing tothis relative movement the annular sleeve is subject to wear. Since the gripping device only grasps the free end of the bobbin tube, which. end projects overthe winding, a high pressure is also required in order to produce a sufficiently great clamping of the bobbin tube.

Furthermore, as a result of the fact that the folds, which are formed at the inner part of the annular sleeve during the inflation of the gripping device, are supported on the moving outer part of the annular sleeve, the directional stability during the retaining of the bobbin tube is impaired. The known pneuma tic gripping device is therefore less suitable for the mounting of bobbin tubes on spindles or pins which requires a high degree of directional stability.

It is the object of the invention to provide a pneumatic gripping device which avoids these dis advantages and in the case of which, with the economic construction which is advantageous to manufacture, no relative movement of the sleeve GB 2 118 523 A 1 with respect to the housing wall occurs.

In accordance with the invention this object is achieved in that the gripping device housing and the sleeve are bell-shaped and the sleeve is inserted in the gripping device housing, wherein the sleeve engages overthe open edge of the gripping device housing and is pressed against the edge in an airtight manner by a screw collar ring.

It is thus now possible to produce the gripping device in a structurally simple and economic manner, which is of particular importance when it is used in the case of stationary bobbin changing devices which have a plurality of gripping devices. Moreover, as a result of the construction according to the invention, it is achieved that the bobbin tubes and the bobbins or cops are held in a directionally stable manner by the gripping device, since the folds of the sleeve which form during inflation are supported against the rigid wall of the gripping device housing.

The directionally stable gripping and holding of the tubes and the bobbins is further improved in a further construction of the invention in that the effective gripping length of the gripping device extends over the upper winding layers of the bobbin tube. In this way the contact pressure, required for a reliable clamping of the bobbin end in the gripping device, is also reduced so that the gripping device may be used for all types of bobbin tubes, even for tubes with extremely thin walls. An adaptation of the shape of the gripping device to the free end of the bobbin tube and the conical tip adjacent thereto is achieved in that the upper parts of the gripping device housing and the sleeve are essentially cylindrical and the lower parts thereof are conical. As a result of this, the axial force of reaction occurring when the bobbin is grasped is reduced. The contact pressure of the sleeve on the outer periphery of the bobbin or bobbin tube may be locally varied by a different wall thickness of the sleeve. Advantageously the wall thickness of the sleeve section which may be pressed against the free end of the bobbin tube and is essentially cylindrical is smaller than that of the conical section, as a result of which the force component effective in the direction of the spindle bearing is further reduced.

In a preferred arrangement the gripping device housing comprises bores at its front face, through which bores compressed air may be introduced into the space between the gripping device housing and the sleeve. The gripping device may thereby be simply secured to its gripper bar extending along the spinning or twisting machine and connected to a compressed air duct integrated in the gripper bar. It is thus provided thatthe outer edge of the frontface of the gripping device housing is a sealing surface resting againstthe gripper bar.

Further advantages of the invention will result from the following description of an embodiment, made with reference to the attached drawings, in which:

Figure 1 shows a longitudinal section of a pneumatic gripping device in the construction according to the invention in the pressureless state; Figure 2 shows a longitudinal section of the GB 2 118 523 A 2 gripping device according to figure 1 acted upon by compressed air; and Figure 3 shows a cross-section through the gripping device according to figure 2 on an enlarged scale.

In figure 1,1 designates a pneumatic gripping device which is lowered onto a bobbin (cops) and consists of a bell-shaped gripping device housing 2, a sleeve 3, which is inserted in the gripping device housing 2 and is likewise bell-shaped, and a screw collar ring 4. The bell-shaped sleeve 3 inserted in the gripping device housing 2 engages over the open edge 20 of the gripping device housing 2 and is pressed in an airtight manner against the edge 20 by means of the screw collar ring 4 which is pressed on the gripping device housing 2 and is locked thereon. The sleeve 3 consists of a resiliently deformable material, whereas the gripping device housing 2 is advantageously produced from an inherently stable plastics material.

The gripping length of the gripping device 1 predetermined by the sleeve 3 is preferably dimensioned such that it extends over the upper winding layers of the bobbin Sp. For the adaptation to the approximately cylindrical free end of a bobbin tube 5, forming the core of the bobbin Sp, and to the conical yarn winding of the tube, which winding is adjacent the free end of the bobbin tube 5, the upper part a of the sleeve opposite the free end of the bobbin tube 5 is essentially cylindrical and its lower part, opposite the upper winding layers, is conical. The gripping device housing 2 is adapted to this construction of the sleeve 3.

In order to alter locally the gripping strength of the gripping device 1 and the sleeve 3, the wall of the sleeve 3 is constructed with varying thickness, preferably in the manner shown in figures 1 and 2 such that the thickness of the wall of the essentially cylindrical section a of the sleeve is less than that of the conical part connected thereto. Advantageously the thickness of the wall of the bell base of the sleeve corresponds or is similar to that of the conical part.

The supply of compressed air into the space between the gripping device housing 2 and the sleeve 3 occurs through at least one bore 6 in the front face 21 of the gripping device housing. If necessary the bore may also be provided in a side wall of the gripping device housing 2. in a preferred arrangement, the front face 21 of the gripping device housing 2 has four bores 5, wherein in each case two of the bores 5 disposed on a circular path are opposite one another. The gripping device 1 is rigidly secured by means of a screw 10 to a gripper bar 7 of a stationary bobbin changing for which it is particularly intended, the gripper bar 7 extending along the row of spindles of a spinning or twisting machine. The gripping device 1 may, of course, also be used in the case of a bobbin changer which travels along the row of spindles. Advantageously the screw 10 used for the detachable securing is arranged asymmetrically in the gripper bar 7 and symmetrically in the gripping device 1.

Integrated in the gripper bar 7, which bears a number of gripping devices 1 corresponding to the number of spindles and may be moved up and down 130 in a known manner, is a compressed air duct 8 connected to a compressed air source. Thus the gripper bar 7 is used simultaneously as a compressed air duct. A bore 80, which leads radially away from the compressed air duct 8, connects the compressed air duct 8 to the bores 6 in the front face 21 of the gripping device housing. In order to enable compressed airto be supplied to all four bores 6, the outer edge 22 of the front face 21 is raised up so that only this edge rests againstthe wall of the gripper bar 7 and there is a circular cavity 9 between the face of the front face 21, containing the bores 6, and the gripper bar 7, into which cavity 80 the bore 80 leads. In this connection the edge 22 surrounding the cavity 9 is simultaneously used as a sealing surface which seals the cavity 9 against the outside air. An 0-ring 23 may also be inserted in the front face 21 as an additional sealing means. The radius of the cavity 9 is greater than the distance between the central point of the screw 10 and the outer wall of the bore 80.

In order to grasp a bobbin Sp located on a spindle 50 the gripping device 1 according to figure 1 is lowered onto the bobbin, the upper bobbin end passing into the opening formed by the screw collar ring 4 and the bellshaped sleeve 3. The insertion of the bobbin end into the gripper opening is facilitated by the opening of the screw collar ring 4 being constructed in a conical manner. Subsequently compressed air is led to the compressed air duct 8 and flows through the bore 80 and the bores 6 into the space between the gripping device housing 2 and the sleeve 3. The sleeve 3 is thereby inflated and pressed against the outer periphery of the bobbin end, the essentially cylindrical part a of the sleeve 3 abutting against the free end of the bobbin tube 5 and the conical part abutting against the upper layers of the winding. In this connection, owing to its smaller wall thickness, the contact pressure of the cylindrical part a is greater than that of the conical part of the sleeve 3, so that damage to the yarn layers is avoided and the force component occurring during pressing, in the direction towards the spindle bearing is reduced. In addition, this construction of the sleeve 3 results in only a small amount of air being required for a sufficiently great contract pressure.

As a result of the supply of compressed air into the gripping device 1 the internal diameter of the bell-shaped sleeve 3 is reduced and folds 30 form (figure 3), which divide the space between the gripping device housing 2 and the sleeve 3 into cells. The folds 30 are supported on the inner wall of the gripping device housing 2. Since the gripping device housing 2 is rigid, the bobbin Sp is retained clamped in a directionally stable manner by the sleeve 3 so that it may be mounted on a holding device, for example a pin or cup of a conveyor belt, with a high degree of accuracy after being removed from the spindle 50 by raising the gripping device. An empty bobbin tube, grasped by the gripping device 1, may be mounted on a spindle 50 of the spinning or twisting machine with the same degree of accuracy. After the bobbin Sp has been mounted on the holding device the air is removed from the gripping device 1. The compressed air thus flows through the 2 1 f 3

Claims

four bores 6 and the bore 80 into the compressed air duct 8, which occurs just as rapidly and reliably as the introduction of the compressed air into the gripping device 1. CLAIMS

1. A pneumatic gripping device for bobbin changing devices on spinning or twisting machines, which contains a gripping device housing and a resiliently deformable sleeve which is disposed in the gripping device housing and may be pressed against the outer periphery of a bobbin tube, characterized in thatthe gripping device housing and the sleeve are beil-shaped and the sleeve is inserted in the gripping device housing, wherein the sleeve engages over the open edge of the gripping device housing and is pressed in an airtight manner against the edge by means of a screw collar ring.

2. A pneumatic gripping device as claimed in claim 1, characterized in that the effective gripping length of the gripping device extends overthe upper winding layers of the bobbin tube.

3. A pneumatic gripping device as claimed in claim 1 or 2, characterized in that the upper parts of the gripping device housing and the sleeve are substantially cylindrical and their lower parts are conical.

4. A pneumatic gripping device as claimed in claims 1 to 3, characterized in that the wall of the sleeve is of varying thickness.

5. A pneumatic gripping device as claimed in claim 4, characterized in that the thickness of the wall of the substantially cylindrical section, of the sleeve, which may be pressed against the free end of the bobbin tube is less than that of the conical section.

6. A pneumatic gripping device as claimed in any of claims 1 to 5, characterized in that the gripping device housing comprises bores on its front face, through which bores the compressed air may be introduced into the space between the gripping device housing and the sleeve.

7. A pneumatic gripping device as claimed in any of claims 1 to 6, characterized in that the gripping device is rigidly secured to a gripper bar, which extends along the spinning or twisting machine, and is connected to a compressed air duct integrated in the gripper bar.

8. A pneumatic gripping device as claimed in claim 7, characterized in that the outer edge of the frontface of the gripping device housing is a sealing surface abutting againstthe gripper bar.

9. A pneumatic gripping device as claimed in claim 8, characterized in that the sealing surface surrounds a cavity into which there opens a bore leading away from the compressed air duct.

10. A pneumatic gripping device as claimed in any claims 7 to 9, characterized in that the securing means for the gripping device is disposed asymmetrically in the gripper bar and symmetrically in the gripping device.

11. A pneumatic gripping device constructed substantially as hereinbefore described with refer ence to, and as shown in, the accompanying draw ings.

GB 2 118 523 A 3 Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd., Berwick-upon-Tweed, 1983. Published atthe Patent Office, 25 Southampton Buildings, London, WC2A lAY, from which copies may be obtained.